An FT-IR study of the adsorption and reactivity of ethanol on systems derived from Mg2Al–W7O246− layered double hydroxides

Abstract

A FT-IR spectroscopy study on the surface reactivity of MgAl-paratungstate LDHs calcined at 500 and 700 °C, prepared by anion exchange from a Mg₂Al-nitrate hydrotalcite and precursor salt (NH₄)₁₀H₂W₁₂O₄₂, for ethanol dehydrogenation, is reported. Calcination at 300 °C of Mg₂Al–W₇O₂₄⁶⁻ LDH leads to amorphous species, and crystallisation of MgWO₄ is observed at 700 °C. The solids calcined at 500 and 700 °C exhibit surface Lewis acid sites and are selective to acelaldehyde formation during ethanol dehydrogenation or to oxidative dehydrogenation, especially in the sample calcined at 500 °C, where carboxylate species are not detected in the temperature range tested (room temperature to 300 °C).